Lab
Simple Pendulums: LabPro Data
Printer Friendly Version
Purpose
To let students become familiar with measuring with LabPros, meter sticks, and triple beam balances, identifying vibrations and to develop critical thinking skills. Secondly, to introduce student to a technique of data analysis using linear regression.
Equipment
Each group needs the following equipment:
2 meters of string
1 LabPro attached to a computer station
1 desktop trapeze
1 meter stick
1 triple beam balance
1 2-hole stopper
1 1-hole stopper
1 200-gram mass
Procedure
Students will work in teams of two or three. On each team, one member will manipulate and measure the suspended pendulums, a second member will operate the LabPro, and the third member will record the data provided in the group's data chart.
The team member working with the pendulums must initially measure the length of each pendulum using 10 washers as the "bob". The
length of a pendulum
is defined as the distance from the pendulum's point of suspension (its pivoting position) to the center of mass of its
bob
(the mass hanging from its end). Between trials, he/she will change the length of the team's pendulum by lowering the cross beam 10-15 centimeters. When releasing the pendulum, make sure that its
amplitude
is very small, less than 15º, as larger angles may result in inaccurate results.
The team member operating the LabPro must make sure that the motion detector is looking directly at the pendulum's bob (2 stoppers) as it swings. The bob should never get closer than 40 cm from the detector during its oscillations. The motion detector can rest on the table or on the floor. When you are ready to run a trial, first start the LabPro by clicking
Collect
, then release the pendulum. Run your trial for 10 seconds. Then highlight the region either between the first and last crest or the first and last trough. Record the "dx" which represents the duration of time highlighted and count the number of intervening vibrations.
The team member recording the data should complete the following data charts.
2-stopper data
trial number 1
trial number 2
pendulum
length (cm)
duration
number of
vibrations
duration
number of
vibrations
Before running the last three trials, we need to record the mass of the two stoppers used as our bob.
mass data
2-stoppers
(grams)
Now replace the 2-stoppers with a 200 gram mass and run three more trials. Let the lengths of these three pendulums be different than those for your original 10 trials.
both stoppers data
trial number 1
trial number 2
pendulum
length (cm)
duration
number of
vibrations
duration
number of
vibrations
Sample Data
In the following blanks, input the information from your original data tables for the
second trial of your 7th-length of the 2-stopper bob
and the
second trial of your 2nd-length of the 200-gram bob
. Do
NOT
add units to your answers; the units are supplied for each column.
second
trial
length (m)
duration (sec)
vibrations
frequency (hz)
period (sec)
7th 2-stopper
2nd 200-gram
Analysis
Using all of your data for the 2-stopper bob and as well as the 200-gram mass, complete the following data chart. Note that there are a total of 13 rows, 10 for the "2-stoppers" and 3 for the "200-gram mass."
pendulum
length
(m)
average
period
#1
average
period
#2
Period
T (sec)
Period
^{2}
T
^{2}
(sec
^{2}
)
The team member working with EXCEL is to open
this worksheet
and input the data from the two green columns in the last chart. Remember that the lengths of your pendulums MUST BE in meters, not centimeters as originally measured.
After you fill in the requested information in column M, save your file in your period folder as
LastnameLastnamePendulum.xls
where each member's last name is included in the file's name.
After your EXCEL file has been completed and saved, come to the print station and print a copy of each file for your lab report and for any group member who would like to keep a copy.
Conclusions and Error Analysis:
What is your group's EXCEL spreadsheet's filename?
1(a) Using the form,
y = mx + b
, write the specific equation for the regression line shown on your printout. Do not use x and y, use the appropriate variables for each axis.
What is the equation of your line?
What are the units on your line's slope?
1(b) Use your graphs's equation to extrapolate the period of a pendulum whose length equals the height of an average flag pole, 10 meters. Show your calculations on your graph's printout.
What would be the period of this pendulum?
2. We will now solve for the gravitational field strength (
g
) in our lab room by using the slope of your regression line. To do this, set the numerical value of your line's slope equal to the expression 4
π
^{2}
/g and solve for the value of
g
.
Since the expression 4
π
^{2}
/g represents the slope of your graphs, the units for measuring
g
would be the reciprocal of the slope's units: sec
^{2}
/m. Hence,
g
is measured in m/sec
^{2}
. Be sure to include these units on your value for
g
. Show your work on your graph's printout.
What is the value of gravity according to your experiment?
3. If the accepted value for the gravitational field strength at sea level is 9.8 m/sec
^{2}
, calculate your experiment's percent error. Show your work on each printout.
The formula to calculate % error is
What is the percent error for your experiment?
4. State an experimental error, procedural or system, and a correction which would minimize its affects on the outcome of future experiments. Perhaps this physlet animation entitled "
The Pendulum
" can give you some guidance.
source of error:
correction:
5. In our original data, there were three pendulums that had more massive bobs. We now want to consider whether the mass of the pendulum's bob affected the frequency of the pendulum. Support your answer by comparing or contrasting the data for the more massive bobs.
Here are some things you might want to think about when discussing your answer: were the results for these masses outliers or did they merge systematically with the results of the smaller masses? were there relatively similar lengths with different masses that had the same or closely related frequencies?
Student Code
Password
Lab Report.
When finished, each lab member is to keep their own copy of the EXCEL graph for their notebooks. As a group, you are to turn in one graph in to the one-way box with your calculations for conclusions #1, #2 and #3.
Related Documents
Lab:
Labs -
A Physical Pendulum, The Parallel Axis Theorem and A Bit of Calculus
Labs -
Calculation of "g" Using Two Types of Pendulums
Labs -
Conical Pendulums
Labs -
Conical Pendulums
Labs -
Conservation of Energy and Vertical Circles
Labs -
Directions: Constructive and Destructive Interference
Labs -
Doppler Effect: Source Moving
Labs -
Frequency of Vibrating Strings
Labs -
Illuminance by a Light Source
Labs -
Inertial Mass
Labs -
Interference Shading
Labs -
Introductory Simple Pendulums
Labs -
Kepler's 1st and 2nd Laws
Labs -
Loop-the-Loop
Labs -
Moment of Inertia of a Bicycle Wheel
Labs -
Oscillating Springs
Labs -
Pipe Music
Labs -
Relationship Between Tension in a String and Wave Speed
Labs -
Relationship Between Tension in a String and Wave Speed Along the String
Labs -
Ripple Tank Checklists
Labs -
Ripple Tank Checklists
Labs -
Ripple Tank Sample Solutions
Labs -
Ripple Tank Student Involvement Sheet
Labs -
Roller Coaster, Projectile Motion, and Energy
Labs -
Sand Springs
Labs -
Simple Pendulums: Class Data
Labs -
Speed of a Wave Along a Spring
Labs -
Speed of Sound in Air
Labs -
Speed of Sound in Copper
Labs -
Video LAB: A Gravitron
Labs -
Video LAB: Circular Motion
Labs -
Video LAB: Looping Rollercoaster
Labs -
Video: Law of Reflection
Labs -
Video: Law of Reflection Sample Diagram
Labs -
Water Springs
Resource Lesson:
RL -
A Derivation of the Formulas for Centripetal Acceleration
RL -
Barrier Waves, Bow Waves, and Shock Waves
RL -
Beats: An Example of Interference
RL -
Centripetal Acceleration and Angular Motion
RL -
Conservation of Energy and Springs
RL -
Derivation of Bohr's Model for the Hydrogen Spectrum
RL -
Derivation: Period of a Simple Pendulum
RL -
Energy Conservation in Simple Pendulums
RL -
Gravitational Energy Wells
RL -
Interference of Waves
RL -
Interference: In-phase Sound Sources
RL -
Introduction to Sound
RL -
Kepler's Laws
RL -
Law of Reflection
RL -
LC Circuit
RL -
Magnetic Forces on Particles (Part II)
RL -
Period of a Pendulum
RL -
Physical Optics - Thin Film Interference
RL -
Resonance in Pipes
RL -
Resonance in Strings
RL -
Ripple Tank Video Guides
RL -
Rotational Kinematics
RL -
SHM Equations
RL -
Simple Harmonic Motion
RL -
Sound Level Intensity
RL -
Speed of Waves Along a String
RL -
Springs and Blocks
RL -
Symmetries in Physics
RL -
Tension Cases: Four Special Situations
RL -
The Doppler Effect
RL -
The Law of Universal Gravitation
RL -
Thin Rods: Moment of Inertia
RL -
Uniform Circular Motion: Centripetal Forces
RL -
Universal Gravitation and Satellites
RL -
Vertical Circles and Non-Uniform Circular Motion
RL -
Vibrating Systems - Simple Pendulums
RL -
Vibration Graphs
RL -
Wave Fundamentals
RL -
Waveform vs Vibration Graphs
REV -
Orbitals
Review:
REV -
Chapter 26: Sound
REV -
Honors Review: Waves and Introductory Skills
REV -
Physics I Review: Waves and Introductory Skills
REV -
Review: Circular Motion and Universal Gravitation
REV -
Sound
REV -
Waves and Sound
REV -
Waves and Sound
Worksheet:
APP -
Big Al
APP -
Echo Chamber
APP -
Ring Around the Collar
APP -
The Dog-Eared Page
APP -
The Satellite
APP -
The Spring Phling
APP -
Timex
CP -
Centripetal Acceleration
CP -
Centripetal Force
CP -
Light Properties
CP -
Reflection
CP -
Satellites: Circular and Elliptical
CP -
Shock Waves
CP -
Sound
CP -
Waves and Vibrations
NT -
Apparent Depth
NT -
Atmospheric Refraction
NT -
Circular Orbits
NT -
Concert
NT -
Light vs Sound Waves
NT -
Pendulum
NT -
Rotating Disk
NT -
Shock Cone
NT -
Sound Waves
NT -
Spiral Tube
NT -
Standing Waves
WS -
Basic Practice with Springs
WS -
Beats
WS -
Beats, Doppler, Resonance Pipes, and Sound Intensity
WS -
Counting Vibrations and Calculating Frequency/Period
WS -
Doppler - A Challenge Problem
WS -
Doppler Effect
WS -
Fixed and Free-end Reflections
WS -
Fundamental Wave Terms
WS -
Illuminance 1
WS -
Illuminance 2
WS -
Inertial Mass Lab Review Questions
WS -
Interference: In-phase Sound Sources
WS -
Introduction to Springs
WS -
Kepler's Laws: Worksheet #1
WS -
Kepler's Laws: Worksheet #2
WS -
Lab Discussion: Inertial and Gravitational Mass
WS -
More Practice with Resonance in Pipes
WS -
More Practice with SHM Equations
WS -
More Practice with the Doppler Practice
WS -
Pendulum Lab Review
WS -
Pendulum Lab Review
WS -
Practice with Resonance in Pipes
WS -
Practice with the Doppler Effect
WS -
Practice: SHM Equations
WS -
Practice: Speed of a Wave Along a String
WS -
Practice: Uniform Circular Motion
WS -
Practice: Vertical Circular Motion
WS -
Pulse Superposition: Interference
WS -
Ripple Tank Review
WS -
SHM Properties
WS -
Sound Vocabulary
WS -
Speed of Sound
WS -
Speed of Sound (Honors)
WS -
Standing Wave Patterns #1
WS -
Standing Wave Patterns #2
WS -
Standing Wave Patterns #3
WS -
Standing Wave Patterns #4
WS -
Static Springs: The Basics
WS -
Universal Gravitation and Satellites
WS -
Vertical Circular Motion #1
WS -
Vibrating Systems - Period and Frequency
WS -
Wave Phenomena Reading Guide
WS -
Wave Pulses
WS -
Waveform and Vibration Graphs #1
WS -
Waveform and Vibration Graphs #2
TB -
25A: Introduction to Waves and Vibrations
TB -
25B: Vibrations and Waves
TB -
25C: Wave Speed
TB -
25D: Interference
TB -
25E: Doppler
TB -
25F: Doppler Effect (continued)
TB -
26B: Speed of Sound
TB -
26C: Resonance
TB -
26D: Beats
TB -
26E: Decibels
TB -
27A: Light Properties
TB -
Centripetal Acceleration
TB -
Centripetal Force
TB -
Decibels and Sound Intensity #1
TB -
Decibels and Sound Intensity #2
TB -
Interference Re-examined
TB -
Refraction Phenomena Reading Questions
TB -
Sound: Mixed Practice
TB -
Waves and Vibrations
PhysicsLAB
Copyright © 1997-2019
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton